ECCouncil 312-50v13 (Certified Ethical Hacker v13) Practice Test 57

Question 560

An authorized security review documents this behavior: A test receives ICMP port-unreachable for one UDP target but receives no reply at all from another. Which mechanism best accounts for the finding?

  1. TCP SYN scan
  2. UDP service discovery
  3. TCP ACK firewall probing
  4. ICMP echo discovery

Explanation

Correct Answer

B:

A UDP scan often cannot distinguish open from filtered ports when no response arrives; ICMP port-unreachable usually indicates the probed port is closed. On affected systems, it is useful to validate ambiguous UDP results with protocol-aware requests; application-specific probes and correlated firewall logs help distinguish a silent UDP listener from network filtering without guessing from silence.

Incorrect Answers

A:

A SYN scan infers open ports from SYN-ACK replies and commonly avoids completing the full TCP connection, subject to privilege and firewall behavior; the test record points specifically to UDP service discovery, not this separate mechanism.

C:

ACK scanning primarily distinguishes filtered from unfiltered paths; it does not establish that an application listener is open; the scenario identifies UDP service discovery, which has a different triggering condition.

D:

ICMP echo discovery tests reachability at the network layer; a live host need not expose an open application port to answer; the defining symptom in the prompt is associated with UDP service discovery instead.

Question 561

During a scoped review the analyst records both conditions: Two services share a secret key and need to detect whether a transmitted API message was altered or forged. Separately, an unmounted SSD from an encrypted business notebook is connected to a forensic workstation but exposes only ciphertext because the authorized unlocking material is unavailable offline. Which TWO interpretations match the evidence? Choose TWO.

  1. RSA-OAEP encryption
  2. Hash collision concept
  3. S-MIME encrypted email
  4. HMAC integrity check
  5. Full-disk encryption boundary

Explanation

Correct Answers

D:

HMAC combines a cryptographic hash with a shared secret to authenticate message integrity; it does not encrypt message contents; it is separately evidenced in the task, rather than being interchangeable with full-disk encryption boundary.

E:

Full-disk encryption protects data at rest against offline media access; it does not stop a logged-in or fully compromised running system from reading unlocked files; its indicators are tied to the full-disk encryption boundary record, not to the finding involving HMAC integrity check.

Incorrect Answers

A:

RSA-OAEP uses randomized asymmetric encryption padding suitable for wrapping short secrets, not for bulk data encryption at high throughput; that behavior is distinct from the HMAC integrity check, full-disk encryption boundary finding being classified.

B:

A cryptographic collision occurs when distinct inputs produce the same digest; fixed-size hashes necessarily have possible collisions, with practical resistance varying by algorithm; the scenario identifies HMAC integrity check, full-disk encryption boundary, which has a different triggering condition.

C:

S-MIME can encrypt message content to recipients' public keys and provide digital signatures; intermediate mail transport need not see message plaintext; the defining symptom in the prompt is associated with HMAC integrity check, full-disk encryption boundary instead.

Question 562

The owner asks for a durable safeguard against the issue demonstrated here: A secure site upgrades plain requests to HTTPS but does not give browsers a remembered transport policy, permitting a hostile network to influence the first connection. What is the best response?

  1. Disable obsolete TLS protocols and weak ciphers after compatibility testing
  2. Canonicalize paths and enforce a fixed document root before file access
  3. Disable unused diagnostic HTTP methods
  4. Deploy a tested HSTS policy and HTTPS redirects

Explanation

Correct Answer

D:

HSTS reduces client downgrade risk; its coverage and includeSubDomains settings must reflect actual subdomain TLS readiness. It directly addresses this mechanism: HTTP Strict Transport Security tells compliant browsers to use HTTPS for subsequent requests to covered hosts after receiving the policy securely.

Incorrect Answers

A:

Modern negotiation reduces transport cryptographic exposure while inventorying client requirements prevents avoidable service outages; this is relevant to a separate legacy TLS configuration scenario, rather than the identified exposure; the tested fault instead involves missing HSTS policy.

B:

Resolving canonical paths and checking containment prevents encoding tricks from reaching files outside the approved static content tree; the tested weakness is missing HSTS policy, not the static-file path traversal configuration addressed here.

C:

Allowing only required methods reduces unexpected request behaviors without assuming method restrictions compensate for application authorization bugs; that safeguard does not directly close the missing HSTS policy route highlighted by the test.

Question 563

The asset owner wants to stop the verified condition recurring: An enterprise access point supports SAE but keeps an insecure transition path for compatibility with outdated clients, potentially undermining the intended password-authentication benefit. What is the most targeted improvement?

  1. Enable WPA3-SAE and current firmware without unsafe transition settings
  2. Require strong authentication and encryption regardless of SSID visibility
  3. Use certificate-based network access instead of MAC lists as primary security
  4. Enable address randomization and minimize broadcast identifying data

Explanation

Correct Answer

A:

Modern authentication strengthens password exchange, while configuration and software updates address downgrade and implementation risks. This matters for the observed attack path because WPA3-Personal uses SAE rather than the WPA2-Personal PSK handshake, improving resistance to passive offline password guessing under proper implementation.

Incorrect Answers

B:

WPA3 or sound enterprise security protects data and network admission; beacon suppression is not a substitute for access control; it would improve hidden SSID misconception, not directly correct the reported WPA3-SAE authentication issue.

C:

Cryptographic device identity resists simple address cloning and supports independent credential revocation for each managed endpoint; the measure addresses a different trust boundary from the WPA3-SAE authentication finding.

D:

Rotating private addresses and reducing advertisement metadata make long-term association of broadcasts with one device more difficult; the required correction concerns WPA3-SAE authentication, so this is not the targeted control.

Question 564

Operations asks for a practical correction after the test found: An inspection appliance accepts a different overlapping TCP segment than the backend application, so its reconstructed content no longer matches what the server executes. What should the security team recommend?

  1. Normalize TCP streams and enforce consistent retransmission handling
  2. Tune baselines using service context and investigate deviations
  3. Place IPS at protected chokepoints with tuned blocking policies
  4. Limit tarpits to isolated, capacity-bounded defensive use
  5. Allow outbound destinations and ports based on documented application needs

Explanation

Correct Answer

A:

Reconciling overlap behavior at the boundary prevents ambiguous segments from presenting different effective payloads to sensor and endpoint. The underlying condition is that TCP desynchronization exploits differences in stream tracking or overlap resolution, so a detector inspects a byte stream unlike the server's accepted data.

Incorrect Answers

B:

Context-aware thresholds improve signal quality while preserving visibility into behavior that does not match a known static signature; the action is aimed at anomaly-based detection; it leaves the central TCP stream desynchronization condition unresolved.

C:

Inline placement lets signatures or behavior rules prevent delivery, but testing is necessary to avoid blocking legitimate applications; this is relevant to a separate inline network IPS scenario, rather than the identified exposure; the tested fault instead involves TCP stream desynchronization.

D:

Controlled delays may deter automation, but resource limits and exemptions protect legitimate clients from accidental service degradation; the tested weakness is TCP stream desynchronization, not the tarpit delay behavior configuration addressed here.

E:

Least-privilege egress policy blocks unnecessary command-and-control routes while preserving approved business traffic; that safeguard does not directly close the TCP stream desynchronization route highlighted by the test.

Question 565

An incident analyst is asked to classify this observed activity: Two employees exchange confidential mail protected with recipient certificates, but the sender expects everyone on the mail relay to read the content. Which concept is the closest match?

  1. RSA-OAEP encryption
  2. Forward secrecy
  3. HMAC integrity check
  4. Digital signature verification
  5. S-MIME encrypted email

Explanation

Correct Answer

E:

S-MIME can encrypt message content to recipients' public keys and provide digital signatures; intermediate mail transport need not see message plaintext. The appropriate hardening measure is to manage recipient certificates and private keys for encrypted S-MIME messages, since verified certificates and sound key custody enable intended recipients to decrypt content while supporting sender authenticity when messages are signed.

Incorrect Answers

A:

RSA-OAEP uses randomized asymmetric encryption padding suitable for wrapping short secrets, not for bulk data encryption at high throughput; the reported conditions are characteristic of S-MIME encrypted email, not that path.

B:

Forward secrecy uses ephemeral key exchange so recorded session traffic cannot normally be decrypted solely from a later compromise of the server's long-term authentication key; those prerequisites differ from the S-MIME encrypted email behavior in the record.

C:

HMAC combines a cryptographic hash with a shared secret to authenticate message integrity; it does not encrypt message contents; this would classify another type of evidence, whereas the actual finding shows S-MIME encrypted email.

D:

Digital signatures use private-key operations for authenticity and integrity verification by corresponding public keys; confidentiality is a separate service; the relevant mechanism in the observed workflow is S-MIME encrypted email instead.

Question 566

The approved engagement produces this evidence: A TCP port accepts connections, but the assessor must determine whether a TLS handshake is actually supported on that service. What is the correct technical interpretation?

  1. Service version probing
  2. TCP ACK firewall probing
  3. Idle scan inference
  4. TLS endpoint inspection

Explanation

Correct Answer

D:

A TLS handshake probe identifies negotiated protocols, cipher suites, and certificate identity; bare TCP availability does not prove encryption. On affected systems, it is useful to review supported TLS versions and certificate validation on the real service; hardening protocol negotiation and certificate chains prevents downgrade and impersonation weaknesses that a simple open-port scan cannot detect.

Incorrect Answers

A:

Service detection sends protocol-aware probes and interprets server responses; the port number alone does not prove which application is listening; those prerequisites differ from the TLS endpoint inspection behavior in the record.

B:

ACK scanning primarily distinguishes filtered from unfiltered paths; it does not establish that an application listener is open; this would classify another type of evidence, whereas the actual finding shows TLS endpoint inspection.

C:

Idle scanning uses predictable IP ID behavior of a third-party zombie to infer target port state; modern stacks and NAT can frustrate it; the relevant mechanism in the observed workflow is TLS endpoint inspection instead.

Question 567

In a permitted test environment, the analyst records: A flashlight application requests access to SMS and contacts despite lacking any functional need for personal communications data. What is the most precise classification?

  1. Excessive mobile permissions
  2. Mobile overlay credential theft
  3. MDM selective wipe
  4. Mobile dynamic analysis

Explanation

Correct Answer

A:

Overprivileged mobile apps expand the information available after compromise or abuse; the platform permission model should track actual features. The appropriate hardening measure is to review requested permissions and block unnecessary sensitive grants, since feature-based permission review limits unintended data collection and reduces blast radius when an app misbehaves.

Incorrect Answers

B:

Overlay attacks abuse user-interface permissions or accessibility features to impersonate legitimate screens and collect credentials; the relevant mechanism in the observed workflow is excessive mobile permissions instead.

C:

Mobile device management can distinguish corporate-managed data from personal content when supported enrollment and separation features are used; those effects are not the excessive mobile permissions pattern evidenced by the assessment.

D:

Dynamic mobile analysis observes application behavior during execution; it complements static inspection but may miss conditions tied to real hardware; the case demonstrates excessive mobile permissions rather than the alternate mechanism.

Question 568

The post-assessment action plan cites this evidence: A service generates authenticated ciphertext using a fixed per-account encryption key but reuses an IV after a process restart, breaking the mode's nonce-uniqueness requirement. Which corrective measure should be prioritized?

  1. Store salted passwords using tuned Argon2id parameters
  2. Enforce full-disk encryption with secure boot and recovery-key controls
  3. Guarantee unique nonces per encryption key and rotate affected keys
  4. Authenticate ephemeral key exchange with validated peer certificates

Explanation

Correct Answer

C:

Nonce-generation discipline protects the authentication construction, while key rotation limits exposure after uniqueness guarantees have failed. The technical basis for the recommendation is that GCM is an authenticated-encryption mode whose security depends on nonce uniqueness for a given key; reuse can undermine confidentiality and authentication.

Incorrect Answers

A:

Unique salts defeat precomputed matches and memory-hard derivation increases the cost of large-scale cracking of leaked verifiers; it would improve argon2id password storage, not directly correct the reported AES-GCM nonce reuse issue.

B:

At-rest encryption reduces exposure after physical theft, while platform integrity and key escrow govern startup trust and legitimate recovery; the measure addresses a different trust boundary from the AES-GCM nonce reuse finding.

D:

Certificate verification prevents man-in-the-middle key substitution while ephemeral elliptic-curve exchange supports fresh traffic keys; its security benefit applies principally to elliptic-curve key exchange, not the defect described; the tested fault instead involves AES-GCM nonce reuse.

Question 569

A remediation meeting focuses on the following finding: A report builder accepts a user-selected database column name as text, but prepared-statement placeholders do not represent SQL identifiers in the target driver. Which proposed action best addresses its root cause?

  1. Map requested identifiers to an explicit approved field list
  2. Escape only quote characters in unapproved identifier strings
  3. Depend solely on a web firewall keyword list for report columns
  4. Bind the requested column name as an ordinary string parameter

Explanation

Correct Answer

A:

Allowlisting identifiers preserves flexible reports without concatenating arbitrary client text into SQL grammar positions. The safeguard responds to the underlying issue: prepared-statement parameters represent data values, not arbitrary SQL identifiers; dynamic object names must be chosen through trusted code.

Incorrect Answers

B:

Identifier parsing and quoting differ across databases, so ad hoc escaping does not enforce an allowed identifier set; the dynamic SQL identifier control weakness in the question therefore remains uncorrected.

C:

A network filter cannot reliably validate all permissible table and column names within application-specific query grammar; the dynamic SQL identifier control weakness in the question therefore remains uncorrected.

D:

A value parameter represents data rather than replacing SQL grammar or an identifier, so the intended column selection fails; the dynamic SQL identifier control weakness in the question therefore remains uncorrected.

Question 570

In a permitted test environment, the analyst records: A page reads a value from location.hash and assigns it to innerHTML, causing script execution without the server reflecting that value. What is the most precise classification?

  1. DOM-based cross-site scripting
  2. Operating-system command injection
  3. Cross-site request forgery
  4. Reflected cross-site scripting
  5. Stored cross-site scripting

Explanation

Correct Answer

A:

DOM XSS occurs when client-side JavaScript moves untrusted data into a dangerous DOM sink; the server response may be static. A practical defensive response is to replace unsafe DOM sinks with text-safe APIs and validate client data; using textContent or safe templating blocks markup interpretation even when attacker-controlled fragments never pass through the server.

Incorrect Answers

B:

Command injection arises when untrusted text is interpreted as operating-system command syntax rather than a literal argument or data value; the observed evidence concerns DOM-based cross-site scripting instead.

C:

CSRF exploits automatic credential attachment on cross-site requests; it does not require the attacker to read the victim's authenticated response; the test record points specifically to DOM-based cross-site scripting, not this separate mechanism.

D:

Reflected XSS returns unsafely embedded input in the immediate server response; the payload does not need to be permanently stored by the application; that behavior is distinct from the DOM-based cross-site scripting finding being classified.

E:

Stored XSS persists attacker-controlled content server-side and delivers it to later viewers through unsafe rendering; the scenario identifies DOM-based cross-site scripting, which has a different triggering condition.

Certified Ethical Hacker v13 (312-50v13) Practice Tests